Various machines and pieces of equipment or handling lines are currently known for conveying sheet-like products, such as glass sheets and the like, from a storage facility, for example of the type with perpendicular translational motion, to a region for easy handling or working and vice versa.
These storage facilities used in storing glass sheets generally have a plurality of inclined frames which are arranged in a row and are parallel and arranged in a storage area.
Apparatuses for picking up and loading sheet-like products, arranged so as to travel on rails to the side of a row, or between two rows, of inclined sheet supporting frames are currently known for the handling of said sheets.
Such an apparatus, disclosed and claimed in Italian patent 0001280055 of 3 Feb. 1995 in the name of this same Applicant, is characterized in that it comprises:                a truck which can glide on one or more rails,        a supporting structure for a grip assembly, of the type with suckers, for a sheet, said supporting structure being able to perform a translational motion on the truck by way of means for lateral translational motion with respect to the advancement direction of the truck,        a grip assembly for a sheet, which is rotatably coupled to its supporting structure by way of rotation means which are adapted to arrange it from a first raised grip configuration to a second substantially horizontal configuration and vice versa, both on one side, for example forward, and on the opposite side, i.e., backward.        
Said grip assembly, after picking up a sheet from an inclined frame, deposits it horizontally on a bed with motorized rollers which is designed for the translational motion of the sheet on a worktable, generally a cutting table.
The roller bed is substantially structured like a comb, with through openings which are contoured so that they can be crossed downward from above and vice versa by the grip assembly during its rotary motion from the first raised configuration to the second substantially horizontal configuration, when the truck is in a preset position proximate to the bed.
The grip assembly, formed by a series of uprights which are fixed in a lower region to a horizontal tubular element which belongs to the rotation means, turns toward the bed so as to support above itself the sheet retained by the suckers; as the uprights of the grip assembly rotate and descend so as to pass through the openings of the bed, the arrangement of the sheet tends to become coplanar with respect to the roller bed on which it is to be placed.
When the uprights of the grip assembly are in the openings of the roller bed or slightly below said bed, the suckers release the sheet, which rests on the bed.
Once the sheet has been placed completely on the roller conveyance bed, the rollers, by rotating, transfer it to a cutting table, while the grip assembly is available for a subsequent grip operation.
The case is also known in which the transfer of a sheet to a cutting table by a grip assembly mounted on a truck, which is normally of the overhead type, is performed by an associated roller bed for supporting the sheet-like products, again of the type which can be moved on a rail independently of the truck, the bed being provided with tilting means whose purpose is to move the bed from a first substantially horizontal configuration for gliding on rails to a second inclined configuration which is substantially parallel to the sucker-fitted grip assembly.
The operation of the apparatus is simple: the truck is moved until it arrives at the inclined sheet supporting frame, where the sheet-like product to be picked up is stored.
At this point, the means for the lateral translational motion of the grip assembly are actuated so as to produce the translational motion of the sucker-fitted grip assembly until it is arranged in front of the sheet to be picked up.
The sucker assembly is tilted by the angle needed to keep it parallel to the sheet to be picked up and then the suckers are actuated so that they adhere to the sheet.
The grip assembly with the sheet, which in this embodiment is unable to rotate until it is arranged horizontally, then returns to the central position in order to release the sheet onto the roller bed, which is raised so as to face the sheet in order to receive it.
At this point, the bed is lowered, returning the sheet to the horizontal position; here the sheet can be worked, if means for cutting or means for other kinds of work are associated with the bed, or can be handled easily by means of the support and gliding rollers.
The bed or worktable which can be lifted eliminate the risk of the sheet falling in case of a malfunction of the sucker system, but equipment which comprises them, while being widespread and widely appreciated commercially due to their excellent reliability and practicality, has limitations.
For storage facilities, glassworks and other similar storage areas of small size, the conveyance bed, be it of the comb or liftable type, in fact causes a substantial space occupation and requires a portion of the rails at the end of the stroke to be specifically provided for its temporary parking in order to allow said bed to not hinder the movement of the truck which supports the grip assembly and allow said truck to perform a translational motion at all of said inclined frames that form the magazine.
Further, the manufacture and setup of a roller bed, both of the comb type with through openings for the grip assembly and of the liftable type, is a substantial cost in the overall economy of the apparatus, both in terms of material and in terms of labor for producing it and assembling it.
Moreover, the rise of the bed or table so as to receive the sheet and the subsequent descent for the transfer of the sheet to a workstation, or for sending to working in the case of the table, require a certain time; this time interval keeps the grip assembly busy and said assembly is no longer available in such situations for a subsequent movement for a new grip operation, at least in the rising action.